Cam-shaft driving mechanism for internal-combustion engines



Jan. 14, 1930. w. o. WARNER CAM SHAFT DRIVING MECHANISM FOR INTERNAL COMBUSTION ENGINES 1925 2 Sheets-Sheet 1 Filed April 10 INVENTOR %AL/fl d %,ewE/e BY AT RNEY Jan. 14, 1930. w. o. WARNER 1,743,173

CAM SHAFT DRIVING MECHANISM FOR INTERNAL COMBUSTION ENGINES .7

Filed April 10. 1925 2 Sheets-Sheet 2 INVENTOR Patented Jan. 14, 1930 PATENT OFFICE.

WILLIAM O. WARNER, OF KENMORE, NEW YORK, ASSIGNOR T CURTISS AEROPLANE & MOTOR CO. INC., A CORPORATION OF YORK CAM-SHAFT DRIVING- MECHANISM FOR INTERNAL-COMBUSTION ENGINES Application filed April 10, 1925. Serial No. 22,239.

My invention relates to internal combustionengines and is more particularly concerned with the cam shaft driving mechanism thereof.

Ordinarily the cam shaft driving mechanism, and hence the cam shaft, cams and valve gear of an internal combustion engine, are subjected to the torsional vibrational stresses of the engine crank shaft, which, in an aero- 1 nautical engine, are ofttimes exceedingly,

in no way related to nor does it form, in a single instance, a part of the cam shaft driving mechanism. Usually the propeller shaft gearing is mounted at the propeller end of the motor and the cam shaft driving mechanism is mounted at the anti-propeller end,

such an arrangement necessitating a duplication or multiplicity of gears and shafts, all of which gears and shafts tend to increase materially the complexity, the weight per horsepower, and the production cost of the engine. In an aeronautical motor, anything tending to increase the weight per horsepower, the complexity, the size and the cost thereof, without improved performance, should by all means be eschewed.

By the present invention, instead of proriding, at opposite ends of the engine, mechanism, for driving a propeller shaft and separate mechanism for driving the cam shaft, it is proposed to combine the two, i. e., drive the cam shaft and its associated valve gear thru shafts and gearing directly geared to a large reduction gear forming an actual part of the propeller shaft driving mechanism. Preferably such large reduction gear has associated with it a spring coupling of more or less con ventional design, which coup-ling, in view of 50 its relation to the cam shaft driving mechanism, relieves the latter, and also the crank shaft, of all torsional vibrational stress. Moreover, in combining the driving mechanisms, the weight per horsepower and the production cost of the engine are very appreciably reduced, a lesser number of gears and shafts arerequired to be used, and a more compact engine structure is the result. Obviously such important considerations are greatly to be desired in an aeronautical engine as distinguished from an engine designed fora different use.

In the drawings, wherein like reference characters denote like or corresponding parts,

Fig. 1 is a semi-diagrammatic end elevation, partly'in section, of an aeronautical en'- gine, showing the relative arrangement of the shafts and gearing constituting the cam shaft driving mechanism and the propeller shaft driving mechanism which forms a part thereof;

Fig. 2 is a similar view, in side elevation, of the mechanism illustrated in Fig. 1;

Fig. 3 is a face view of the large reduction gear with a portion of the outer gear covering removed, showing in part the spring coupling which is built into and made an actual part of the said reduction gear;

Fig. 4 is a transverse sectional view of the reduction gear of Fig. 3, and

Figs. 5 and 6 are views similar to Fig. 1

illustrating slight modifications of the cam I shaft driving mechanism.

The invention, while illustrated in connec tion with the so-called V and W type motors,

can be equally as well used in connection with motors of the straight line type. If used in connection with a V type motor, parts of the cam shaft driving mechmanism are duplicated. If used in connection with a W type motor, such parts instead of being duplicated, aretriplicated. Whetherornotduplicationor triplication is required depends wholly upon whether or not there are two or more cylinder banks. In Fig. 1 ofthe drawings aV type motor is shown. In Figs. 5 and 6 W type motors are shown. Such motors, regardless oftype, in-

elude a crank case 10, a crank shaft 11, a propeller shaft 12, and over-head cam shafts 13, two for each cylinder bank. (One, instead of absorb all torsional vibrational stresses occurring in operation. I

The reduction gear 15 and its associated spring coupling 16 have been heretofore employed. Prior structures, however, call for an independent andwholly disassociated cam shaft driving mechanism. Usually the cam shaft driving mechanism is mounted at the end of the engine opposite to the reduction gear, i. e., the anti-propeller end. In the present invention a novel combination is effected. Instead of providing an independent cam shaft drive, the cam shaft drive is directly associated with the large reduction gear. The reduction gear may be therefore said to constitute an integral partof the cam shaft driving mechanism.

From the large reduction gear 15 motion is transmitted to a spur gear 17 mounted on a stub shaft 18 having an axis of rotation directly aboveand parallel with the axis of rotation of the propeller shaft. Said spur gear 17 is at all times in mesh with thelarge reduction gear. The shaft 18 is further provided with a bevel gear 19. In the V type motor of Fig. 1 and in the W type motor of vFig. .5, all of the several cam shafts are indirectly driven from said bevel gear, and from said bevel gear-19, shafts 2O radiate, one shaft 20 being extended off from the bevel gear in the direction of each cylinder bank. Each shaft. 20 carries at its opposite ends bevel pinions 21 and 22, the former being in mesh with the bevel gear 19-and the latter being in mesh with a bevel gear 23 mounted on a stub shaft 24', journaled in bearings (not shown) provided at the outer end of each cylinder bank. In addition to the bevel gear 13, each shaft 24 .is provided with a spur gear 25, said gear being in mesh with duplicate spur gears 26 mounted one each on each ofthe respective cam shafts 13. Where but a single cam shaft is provided for each bank this duplication of gears 26 may be dispensed with.

In Fig. 6 of the drawings a slightly modified arrangement of shafts and gearin is shown. In said figure, instead of driving the respective sets'of cam shafts 13 from the bevel gear 19, the cam shafts of the two outer cylinder banks are driven from the bevel gear 23 provided at the outer end of the center cylinder bank. In other words, the shafts 20 radiate from the bevel gear 23 of the center cylinder bank instead of from the bevel gear r 19 mounted on the stub shaft 18.

From the above, it will be observed that the cam shaft drive mechanism enters into and forms an actual part of the propeller shaft driving mechanism, such dual use of the latter mechanism permitting a great saving of weight. It is the old practice to provide suitable cam shaft driving mechanism at the anti-propeller end of the motor and the propeller shaft driving mechanism at the propeller end, and while such an arrangement is instrumental in relieving the cam shafts'and the valve gear associated therewith from torsional vibrational stresses, it nevertheless adds very appreciably to the weight of the motor considered at a whole.

While I have described my invention in detail in its present preferred embodiment, it willbe obvious to those skilled in the art after understanding my invention, that Various changes and modifications may be made therein without departing from the spirit or scope thereof. I aim in the appended claims to cover all such modifications and changes.

What I claim is: v

1; In an internal combustion engine, a pluralityof banks of engine cylinders, a crank shaft, an over-head cam. shaft for each cylinder bank, a large reduction gear driven off the crank shaft, cam shaft driving mechastresses due to irregularities in the rotation of said propeller shaft.

v 2. In an internal combustion motor, a crank shaft, a cam shaft, a direct connection between said crank shaft and said cam shaft including a reduction gear, a propeller shaft, and a yielding driving connection between said reduction gear and said propeller shaft.

' In testimony whereof I hereunto aflix my signature.

WILLIAM O. WARNER. 

